Category Archives: How-to

Using MapTips in ArcGIS

Posted on by

It is often useful in a map to enable “MapTips” for layers in an ArcMap document. When map tips are on, hovering the cursor over a feature on the map will display the contents of a field from the attribute table in a pop-up window. This eliminates the user’s need to use the Identify tool on a layer.

To turn on map tips, open properties for the layer and choose the Display tab. In the Display Expression box, select the field you would like shown in the pop-up and check “Show map tips using the display expression“.

However, you may find this option unavailable (“grayed out”) when trying to enable map tips.

This is usually caused by the layer not having a spatial index available (see this post from ESRI for more information). The solution is to build a spatial index. This may be accomplished two ways:

1) in ArcCatalog, navigate to the layer, select it, and open Properties. Choose the Indexes tab and click Add under Spatial Index.  

2) use the Add Spatial Index tool. In Arc Toolbox expand Data Management Tools > Indexes  and open the Add Spatial Index tool. Select your layer as the Input Features in the tool and click OK.

An advantage to using the ArcToolbox tool is it may be used to rebuild an existing spatial index. ArcCatalog may only be used to create an index if one does not already exist.

After creating a spatial index, the Show MapTips option should be available for your layer.

Instructions for installing the Education Edition of ArcGIS (1 year license)

Posted on by

I have had some questions about how to install and authorize the 1-year ArcGIS license available for education use. I improved the directions, available as a PDF or continue to read below… If you are interested in the software, installer DVDs are available from the help desk in the Library.

ArcGIS 10 Education Edition – 1 Year Licensed Software

The Education Edition of ArcGIS version 10 requires an authorization number that must be activated before use. An authorization number will be printed on the inside of the DVD sleeve, along with instructions for activating it. Visit www.esri.com/EducationEdition to activate the authorization number before installing the software. An ESRI Global Account is required. (If you do not already have an ESRI Global Account, you can create one at this website.)

FAQs for the software are available at   http://www.esri.com/software/arcgis/eval-help/index.html

Please note that the some of the FAQs currently are designed for the general purpose evaluation license, and any reference to the length of the evaluation term should be disregarded. The term of the Education Edition is 365 days and the license level is Arclnfo.

•Insert the DVD and choose ArcGIS Desktop  Setup

•Wait for the installer to load (authenticate as administrator if necessary), accept the license agreement, choose a Complete install, and install to the default location.

•After the install completes, click Finish and choose ArcInfo (Single Use). Click Authorize Now and choose “I have installed my software and need to authorize it”, “Authorize with ESRI using the Internet”, enter contact information, and enter your authorization number. Choose “I do not want to authorize any extensions” (and don’t evaluate any extensions either – they are included with your license).

You should download and install the latest service packs periodically, available from http://www.esri.com/ Support> Downloads: Patches and Service Packs. As of  March 2012, ArcGIS 10 SP 4 is current.

If you have questions, please contact mdhyslop@mtu.edu

Add the Buffer Wizard to an ArcMap toolbar

Posted on by

Earlier version of ArcGIS had a ‘buffer wizard’ tool available. This functionality is now housed in the tools “Buffer” and “Multiple Ring Buffer” found in ArcToolbox > Analysis > Proximity. However, if you prefer the wizard interface, it is still possible to add the Buffer Wizard to a toolbar in ArcGIS. The instructions below are for ArcMap 10.x

  • Customize > Customize Mode…
  • Click the Commands (center) tab
  • Scroll down in the Categories list until you find Tools. Click once to select it.
  • Find the Buffer Wizard in the Commands: list on the right
  • Drag the Buffer Wizard icon to any existing toolbar (I suggest the “Tools” toolbar) and drop it wherever you like
  • Clicking the Buffer Wizard icon will launch the wizard…

You can customize any ArcMap toolbar in this fashion. See the ArcGIS help topic “adding a command to a toolbar or to the main menu” for more information.

ArcGIS Geoprocessing tools

Posted on by

Long-time users of ESRI products may remember the “Geoprocessing Wizard” tool that was available in ArcView 3.x and in ArcGIS 8. Though it was handy to have these common analysis tools in one location, this wizard was removed in ArcGIS 9 and the associated tools were ‘relocated’ to other toolboxes.

The functions of the Geoprocessing Wizard included: Merge, Clip, Intersect, Union, and Buffer

These tools may be found in the following toolboxes (both in ArcGIS 9 and 10):

Merge: Data Management Tools > General > Merge
*the Merge tool was called ‘Append’ in ArcGIS 9.0 and renamed in version 9.1 and later
Clip: Analysis Tools > Extract > Clip
Intersect: Analysis Tools > Overlay > Intersect
Union: Analysis Tools > Overlay > Union
Buffer: Analysis Tools > Proximity > Buffer (or Multiple Ring Buffer)

A fix for ‘script errors’ when running tools in ArcToolbox

Posted on by

I recently was made aware of a fix for the long-present problem with ArcGIS on domain machines (i.e., users log in to lab or office machines using their ISO password) where a script error is generated every time a tool in ArcToolbox is opened. After dismissing three error dialog boxes, the tool will run ‘normally’. Not a fatal error, but annoying.

The problem stems from Internet Explorer, and can be fixed by replacing two files in \program files(X86)\ArcGIS10.0\ArcToolbox\Stylesheets

A description of the fix and the replacement files are available from http://support.esri.com/en/knowledgebase/techarticles/detail/38099

Administrator privileges are needed to implement the fix.

Advanced ArcMap labeling techniques

Posted on by

There’s a new blog entry at ESRI’s Mapping Center that describes how to use variable depth masking to improve the readability of labels on data-dense maps. In the article, a contour map is created with variable depth masking applied to the labels. This technique hides portions of layers under the labels, which makes them easier to read. An ArcInfo-level license is needed to use variable depth masking.

Georeferencing scanned images in ArcGIS

Posted on by

Georeferencing is the process of assigning a coordinate system to a scanned image (map, aerial photo) in GIS. A georeferenced image does not have all scale (vertical scale) distortion removed, so if you georeference an air photo with a large amount of vertical relief across the scene, the scale of the image and the accuracy of the alignment will vary across the scene. For scanned maps, the fit should be better, as nearly all maps are planimetric (designed with scale distortions removed).

To georeference a hardcopy map or photo, you will need both a high-quality scan of the original, plus a reference layer. The reference layer can be in any coordinate system, but you should have five points that you can see on both the scanned image and the reference layer. These should be features that are unlikely to move over time, such as road intersections, bedrock outcrops, or street corners.

Once georeferencing has been applied to your scan, you may use it in conjunction with other layers either as a backdrop for a map or as a source from which you can create new features. The quality of the original map or photo, the resolution of the scan, and your ability to locate high-quality control points will all affect how well the georeferenced image will fit with other features in your GIS.

Here is a document that describes the georeferencing process in ArcGIS. The instructions should work for both ArcGIS 9.x and 10.x.

DNRGarmin and newer Garmin GPS models

Posted on by

Newer versions of Garmin GPS units (Colorado, Oregon) do not connect to your computer in the same fashion as the older models (GPSMap 76, GPSMap 62). These newer Garmins mount their internal storage as a drive letter, e.g., “E”, similar to mounting a flash drive or external hard drive.

To download data from one of these units to DNRGarmin, Go to File->Load From->File… Select “GPX” as the file type and navigate to your GPS’s drive (the drive letter that shows up when you plug in your device). You’ll find a folder housing a bunch of GPX files with time-stamp names. Those contain your waypoints. Select one to load it into DNRGarmin and then save out to a new file (text file for backup or shapefile for use with ArcGIS).

To upload from DNRGarmin to the GPS, go to File–>Save To–>File… and save a GPX file to the same location on your GPS as that you downloaded from above.

Transferring track history points should work in the ‘normal’ DNRGarmin fashion.

Note I do not have access to one of these newer units – these instructions are written from “help me” postings I have found online. If you have an Oregon or Colorado unit and would like help using DNRGarmin, I will be happy to do so (and can then verify these instructions).

mdhyslop at mtu.edu or 7-2308

Store relative pathnames for layers in ArcGIS

Posted on by

By default in ArcGIS 10, full pathnames are stored for all layers you add to a map. This means if you have a file located at c:\data\hydro\rivers.shp that’s used in a map, the full pathname (c:\data\hydro\rivers.shp) to the layer is stored in the map document. ArcMap will always look in c:\data\hydro for the file rivers.shp. Using relative pathnames allows you to move map documents and layers around, as long as the relative locations of the map document and the data don’t change, e.g., as long as the map.mxd map document and the folder data (containing a subfolder hydro with the file rivers.shp, shown below) are moved together, ArcMap will still be able to open the map without issues.

To make the change to relative paths for a single map, choose Map Document Properties… from the File menu and check Store relative pathnames to data sources.

If you want all your new maps to be stored with relative paths you will need to specify relative paths as the default. To do so, click Customize > ArcMap Options… to open the ArcMap Options dialog box, and then click the General tab. Check the option to Make relative paths the default for new map documents. This setting is stored in the registry.

Why should you care about these settings? If you move map documents and data around, say on a flash drive or portable hard drive, these devices can be assigned different drive letters (e, f, g, i…) depending on what computer they are plugged into. If the drive letter changes between sessions and you are using full path names, ArcMap will be unable to find some, or all, layers in your map, and you will be presented with an exclamation point next to the ‘missing’ layers:

 Speaking from personal experience, it is a pain to have to re-connect more than a few missing layers, and some maps have dozens. What’s the process to fix a missing layer?

  • Open the layer’s properties, either by double-clicking on the layer name or right-clicking on the layer and choosing Properties…
  • Click the Source tab and then the Set Data Source… button, browse to the layer’s location on your computer, select it, click add, then OK.
  • Repeat for each missing layer.

To avoid having to repair any map documents in this fashion, you should either a) never move your map documents and associated files around, or b) use relative pathnames, and store your map documents and data in the same directory (or subdirectories).